Telegraph signaling system



July 7, 1925. 1,544,638

' J. M. FELL TELEGRAPH SIGNALING SYSTEM Filed July 12 1921 Jhvm far:

JM/Zea.

ATTORNEY tain Improvements in Systems, of which the Patented July 7,

I UNITED STA HACKENSACK, NEW JERSEY, ASSIGNOR TO JOHN M. FELL, or

AND TELEGRAPH COMPANY,

v A ERICAN TELEPHONE CORPORATION on NEW YORK;

'ljELEGRAlPl-I SIGNALING SYSTEM.

Application filed m 12,1921. Serial No. 484,120.

cation.

This invention relates to telegraph signaling systems, and

Telegraph Signaling following is a specifiparticularly to. means for automatically opening. a local circuit when the line circuit is not in use.

7 In the so-called closed type of line circuit when signals are not being transmitted by any of the stations connected with the line circuit, the keys are closed and current-flows through the said circuit thereby, energizing which are connected 1I1'S6I'18S' the line relays with the line circuit. the line relays keeps their operated position thereby This energization of closing the local circuit, which permits the flow of current therethrough and keeps the signal indicating device in thes operated posltion.

aid local circuit man In telegraph systems in which signals are received by means of a sounder, the malntenance of the local circuit-in a closed condisignals are not beln though the line circuit is tion is not objectionable since it merely causes the armature of the sounder to be held its contacts. However,

in those systems in which the signaling impulses are rendered audible by atone, as in.-

wireless telegraphy,

the local circuit when to prevent the emission of a continuous tone by the tone producing device. The reception of signals by audible tages over previous renders 1t des rable it is necessary to open the hue 1s not 1n use tones possesses advan known methods, which to adopt it for use in connection with wire lines.)

It is the obj ect of this invention to provide ereby the local circuit may be opened during the period in which,

an arrangement fwh line circint, even closed and the hue I with are energized.

g transmitted over the relays connected there- This invention will be better understood from the following description when read at contact 11, no current will :flow through in connection with the attached drawing of which Figure 1 shows alocal circuit adapted to be opened when t use and Fig. 2 shows for the reception 0 tones.

he line circuit is not in a local circu t arranged f telegraph signals armatures in an 2 .line circuit L,which, as stated before, is

sumed that the key,such as line battery 3. The armature move between a frontcontact 5 and a back contact 6. 7 represents any typeof signal indicating device, such as a sounder, having an armature 8 associated therewithand contact 5 of relay 2 and contact 11 of the relay 9 is connected between a source of current 14' and contact 6 of relay 2.;Connected in parallel with the said winding is a condenser 12 and a resistance 13. Althoughthe element 13 is represented as a resistance, it is to be understood that an inductance might be used therefor without varying the scope of this invention." Connectedalso with. the source of current 14 "is the, armature 10 of the relay 9,.which is adaptedto connect the source of current 14 withthe indicating device 7 through the contact 11. The'source of current 14c is shown grounded but it will be apparent that the ground connections could be removed from the said source and from the armature 4 of relay 2 andthe said source and the said armature could be strappedtogether by a conductor other than the earth. Other stations connected with the line L havepreferably the same circuit arrangement as that described above.

Having in-mind the foregoing description .of the parts of this invention and of the circuit in which vention will be clearly understood from the following description of the mode of opera 'tion of the circuit: -Let it be assumed that the of the normally closedtype in which all of the keys (are closed when the circuit is not in operation, thereby permitting the current to flow through the windings of the line relays causing their energization. The flow of current through the-winding of relay 2 causes its armature 4 to touch its contact 5 in the manner shown in Fig. 1. Since the circuit of the winding of'the sounder 7 is open signals are. not .being transmitted over the sounder, consequently its armature will be in a released position. Let it be .as-

1, at any of the stations-connected with the line L is. opened for the transmission of signals. The openthey are embodied, the in- TES PATENT OFFICE...

having its winding. connected between the control relay 9. The winding of the control ingofthe line circuit causes-therelay 2 to release, there-by permitting its armature 41 to. fall back-and touchthecontact 6. Then.

this occurs, current will flow from theYbattery 14, throughthe Winding of the control relay 9, to ground through-"the armature l. Simultaneous wlth the flow of current through the windingof'relay 9. .the.con-.

denser 12, .which is connected in parallel therewith; will be charged bycurrent from the source 14:. .Theflow or current through the winding of rela'y -9 will cause its armature 10 to touchcontact llythereby connecting a source of current 14 with the winding ftl18".SOIl'11Cl6I' 7. Current will not =ilow through the winding oft-he sounder from the said source, since the-circuit is now open at' contact Iii-the transmitting-key connected with'theline L-is now closed, relay 2will be energized andi willcause the armature 4 to touch contact 5,*thereby permitting a how o-f' current from battery 14" through the winding-of the' soun'derto ground through armature t'. This flow of current through. "thewin-ding; of thesounder 7 is rendered possible bythe fact that the armature does not drop baclrandopen its contact-11 as soon'as armature4 opens contact 6, because the energystoredupby the condenser 12 will; discharge through the Winding of the 'con-. trol 'rel'ay 9 assoon as the armature 1' moves away-from contact 6. Thisv discharge of current through thewinding of rel ay 9 keeps the-'relayene-rgized and maintains -its-arn1a-- "'ture in contact'with contact point 11 By properly proportioning the magnitude of thcelements oft-hecircuit containing the condenser,the-resistance:- (or inductance) and;

the windi'ngiof tlie-rontrol" relay, the I rate of -flow of 'current from the condenser-12 throughthe winding of the relay may '-beso governed that the armature 10 will be main-' t-ained' in contact with I the contact point 11 throughout the period of time required for:

i the 'arinature t "to move between its contact points during "the operation f of the 1 trans--- ,mit'ting' key in the linecircuit for the trans-- 1111881011015 signals;- When, l1oWever,.tl1eoperator at the-transmitting station stops the "sending of signals; and clo'ses:his-keyg-thearmature t' wr-ll rem am I -1I1.- contact 1 with I the contact point 53* Whieln' will keep the circuitof' 'the-Windingof therelay r9 open' for a 1 greater le11gth of tiine than is-required to- 3 discharge the "energy 1 or 1 the condenser 12 through the winding rthe cont-r ol: relay 9. 'l h'erefore when 1 thecurrentfrom the said condenserfalls below a certain value, the

armature '10- will drop back {and open the circuitpthrough the sounder '7, thereby releasing its armature: I

The arrangement"shown in Fig. 2 is, in general; Sl-IfllltIFtO the-arrangement shown 1n Fig. 1, excepting that the circuit 11 as been arranged for the reception of signals bymeans tact: with the. contact point 5,-therelay reservoir of energy, suchv as the condenser of? signals: overthe line and the closing of of an audible tone. The. sameparts in both figures have the same designating numerals. In Fig. 2, a receiver 17 and a source of variable E.'M.'F;'18, whi'clris coupled with the circuit ofthe receiver 17' by. means of the trans-former- 1.9, constitutes the receiving element of the local circuit. In the a rangementshoWnin-Fig. 2, whensignals are not being transmitted over the line L, the circuit of the receiver 17 will bezopened at contact point 11, thereby preventing-the constant en'iission oftoneby the receiver 17 which is fixedly coupled: by means of the transformer 19* with a source .18, which: is continuously:

producing .ZlIl available E. M. F. lVhen, however, any key of the line circuit-L is open, them-mature41 w ll dropback against I its contact 6,". thereby energizing the control relay 9- in a. manner cleanly described int: connection with the arrangement shown in Fig; .1. The armature 10 will. be drawn against contact -11,v thereby grounding one side-of the receiver circuit. When the said 9 remainedenergized as a, result ofthe flow. ot':cu1.'nent from the -;condenser 12, so that. its armature "10 did not move a way from contact-11. 7

It will :t-husbe seen; that by means: of a 12, of pnoperproportions, having ;in.circurttherewrth either an. inductance or a resistance 13 and the'wlnding. of relay 9 to contnoltherate of flow-er energy therefrom, the control relay '9 may bemaintained energizedthrougha. period of time in which the circuit connecting it with its primary source of current is open.- By'thepractically continuous: enengizat'ion of the-control relay duning: theg period of the reception of. signals, the: circuit containing the signal indicating; degvi-ce ismaintai-ned in suitable condition for the proper reception of signals.{ With the terminationof the sending the said line circuit in-thevusualamanner, t-he control relay becomes. deenerg z-ed at the end-of a predetermined period of time,

and i the local circuit through: the indicating 2 remains energize-dii This opening; of the circuit prevents the continuous production of ftonebythe-receiver'l'7r- The use of a circuitsuch as shown in Fig. 2 renders poslit] *deviceis openedpeven though, the line relay I Sible the reception ofsignals by m a f 1-180 line relay,

an audible tone and avoids a defect inherent in the use of closed circuits heretofore devised, viz, the continuous production of tone by means of the signal receiving device when the line circuitis not beingused for the transmission of signals. Although armatures I and 10 and the source of current let are shown grounded it will be apparent that the ground connections could be removed and the said parts strapped together by a conductor other than the earth. Although this invention has been dis closed as having a particular form and arrangement of parts, it is to be understood that it is capable of embodiment in other forms and arrangements without departing from the spirit and scope of the appended claims.

\Vhat is claimed is: 1. In a telegraph signaling system, the

combination of a line circuit of the nor-.

mally closed type, a line relay responsive 7 line relay. opens its back contact so as to maintain the partially established circuit of the said indicating device throughout the period of movement ofthe armature of the line relay between its 'front and back contacts during the transmission of signals over. the said line circuit.

2. In a telegraph signaling system, the' combination of a line circuit of the normally closed type, a line relay whose armature moves between front and back contacts, a control relay, the winding of which is connected between the back contact of the said line relay and one side of a source of direct current, the other side of which is eflectively connected with the armature of the line relay, whereby the said control relay will be operated when the armature of the line relay touches its back contact, a condenser connected in parallel with said Wind'- ing of control relay, an indicating device having a source of variable current associated therewith connected between the front contact of the said line relay and a contact of the said control relay, whereby the circuit of the said indicating device will be maintained in closed condition during the period of the reception of signals over the said line circuit and will be opened upon the termination of the reception of the said signals and the restoration of the line circuit to its normally closed condition.

In testimony whereof, I have signed my name to this specification this 11th day of July 1921.

JOHN M. FELL. 

